Mobile Regional Airport
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Mobile Regional Airport clear sky chart from 2005-11-05 to 2017-12-04.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.
Observation TypeMinimum conditions for hour to be usableOut of hours
Clear of CloudsTransparencySeeingSky Brightness
Planetary:50%(no limit)Average(no limit)Nighttime Hours
Deep Sky:70%Average(no limit)5.9Nighttime Hours
CCD Imaging:70%Below AveragePoor(no limit)Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

PlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
Night
59%
15421
24%
47958
19%
15376
64%
15376
32%
28248

By Month

MonthDays of MonthPlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
January1st to 15thNight
40%
720
26%
2158
14%
716
51%
716
30%
1317
January16th to endNight
37%
768
26%
2304
15%
768
46%
768
26%
1460
February1st to 15thNight
41%
704
28%
2107
15%
699
53%
699
32%
1251
February16th to endNight
35%
631
23%
1893
13%
631
44%
631
26%
1217
March1st to 15thNight
41%
720
22%
2160
14%
720
48%
720
28%
1366
March16th to endNight
55%
608
27%
1999
23%
608
60%
608
34%
1105
April1st to 15thNight
51%
539
24%
1797
21%
539
59%
539
31%
1030
April16th to endNight
62%
540
28%
1800
28%
540
69%
540
41%
917
May1st to 15thNight
65%
539
21%
1799
20%
539
70%
539
35%
995
May16th to endNight
75%
561
23%
1693
22%
561
76%
561
36%
970
June1st to 15thNight
76%
540
13%
1620
13%
540
77%
540
34%
955
June16th to endNight
78%
540
16%
1620
17%
540
78%
540
31%
996
July1st to 15thNight
83%
510
11%
1609
12%
510
83%
510
30%
986
July16th to endNight
82%
564
11%
1772
14%
531
82%
531
28%
1098
August1st to 15thNight
85%
539
11%
1788
14%
536
85%
536
31%
1063
August16th to endNight
71%
573
15%
1910
18%
573
71%
573
24%
1228
September1st to 15thNight
74%
576
18%
1836
19%
576
75%
576
29%
1137
September16th to endNight
69%
717
27%
1980
23%
717
70%
717
34%
1203
October1st to 15thNight
69%
720
32%
1980
26%
720
73%
720
46%
1084
October16th to endNight
60%
768
37%
2276
30%
768
68%
768
45%
1183
November1st to 15thNight
63%
760
31%
2435
29%
760
69%
760
39%
1298
November16th to endNight
55%
780
32%
2535
28%
780
64%
780
37%
1345
December1st to 15thNight
46%
736
25%
2391
20%
736
53%
736
29%
1412
December16th to endNight
37%
768
21%
2496
14%
768
46%
768
22%
1632

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

Occurrence of each ForecastData
Points
Cloud CoverDay
11%5%25%5%35%5%6%8%40%
48497
Night
9%42442445%8%47%
48183
TransparencyDay
39%6%11%18%16%6%
48218
Night
33%6%14%19%18%8%
47966
SeeingDay
11%311%21%28%22%
5330
Night
11%417%30%28%8%
15424

By Month

Percentage Cloud Cover SE (2006-)
Color Meanings:
Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
12%5%245%3335%6%45%
1777
16th to endDay
19%6%3432333446%
1920
February1st to 15thDay
14%414324347%46%
1750
16th to endDay
15%435%42435%6%42%
1580
March1st to 15thDay
16%42442445%7%43%
1800
16th to endDay
12%5%24434447%45%
2231
April1st to 15thDay
12%434425%46%7%42%
2151
16th to endDay
10%5%2342445%9%47%
2160
May1st to 15thDay
10%424436%46%9%42%
2151
16th to endDay
8%426%6%36%47%7%41%
2418
June1st to 15thDay
8%5%26%7%46%7%9%11%30%
2340
16th to endDay
8%427%7%5%7%7%9%11%28%
2340
July1st to 15thDay
8%5%38%8%5%8%8%8%10%24%
2250
16th to endDay
8%7%36%7%5%9%7%8%11%24%
2276
August1st to 15thDay
8%5%26%8%5%8%8%9%11%25%
2160
16th to endDay
12%6%36%7%46%6%6%9%29%
2292
September1st to 15thDay
9%5%36%6%46%7%8%8%32%
2112
16th to endDay
7%5%35%5%36%6%46%45%
1980
October1st to 15thDay
7%424323446%54%
1980
16th to endDay
8%32333345%5%56%
1944
November1st to 15thDay
9%414323347%55%
1751
16th to endDay
7%3245%33336%56%
1755
December1st to 15thDay
13%6%25%424346%45%
1651
16th to endDay
20%8%35%5%24346%34%
1728
January1st to 15thNight
14%5%24424345%48%
2158
16th to endNight
18%5%2432434445%
2304
February1st to 15thNight
13%423314346%50%
2103
16th to endNight
16%6%24424445%44%
1893
March1st to 15thNight
13%6%3442445%6%43%
2160
16th to endNight
11%423314347%52%
1999
April1st to 15thNight
10%424325%5%5%7%48%
1797
16th to endNight
7%313323348%57%
1800
May1st to 15thNight
8%32432436%8%50%
1799
16th to endNight
6%4244245%6%11%48%
1693
June1st to 15thNight
4415%436%6%8%13%41%
1620
16th to endNight
4425%5%36%6%7%12%40%
1620
July1st to 15thNight
4214436%8%8%11%42%
1706
16th to endNight
32236%36%7%8%14%38%
1892
August1st to 15thNight
3223436%8%9%15%39%
1800
16th to endNight
7%435%6%35%5%7%10%39%
1910
September1st to 15thNight
6%4245%35%7%8%11%39%
1836
16th to endNight
8%5%25%42346%8%46%
1980
October1st to 15thNight
6%3134235%47%58%
1980
16th to endNight
9%313312246%61%
2276
November1st to 15thNight
7%31442435%5%56%
2435
16th to endNight
8%32432345%5%56%
2535
December1st to 15thNight
12%5%24433446%47%
2391
16th to endNight
18%7%35%424446%37%
2496

Transparency (when cloud cover <= 30%)
Color Meanings:
Too cloudy to forecast Poor Below Average Average Above average Transparent
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
38%27%17%22%11%
1778
16th to endDay
42%3416%23%9%
1920
February1st to 15thDay
36%39%17%21%11%
1752
16th to endDay
41%36%17%22%8%
1580
March1st to 15thDay
39%5%7%21%19%7%
1800
16th to endDay
37%49%19%20%7%
2232
April1st to 15thDay
37%5%8%20%20%8%
2151
16th to endDay
32%5%11%25%20%6%
2160
May1st to 15thDay
35%6%11%20%18%7%
2151
16th to endDay
37%6%13%23%16%2
2422
June1st to 15thDay
40%8%15%23%10%1
2340
16th to endDay
42%9%18%19%8%
2340
July1st to 15thDay
47%12%21%13%4
2118
16th to endDay
47%11%19%18%3
2133
August1st to 15thDay
45%10%22%13%7%
2148
16th to endDay
48%9%17%15%7%2
2292
September1st to 15thDay
41%8%16%17%11%4
2112
16th to endDay
36%6%12%19%17%6%
1980
October1st to 15thDay
29%410%19%23%14%
1980
16th to endDay
28%35%16%26%20%
1944
November1st to 15thDay
29%27%19%29%10%
1751
16th to endDay
29%36%18%25%16%
1755
December1st to 15thDay
39%38%20%20%6%
1651
16th to endDay
49%45%18%16%4
1728
January1st to 15thNight
38%27%15%24%10%
2158
16th to endNight
42%35%14%23%10%
2304
February1st to 15thNight
34%35%19%22%13%
2112
16th to endNight
41%45%15%20%12%
1893
March1st to 15thNight
40%49%17%21%6%
2160
16th to endNight
32%211%21%22%9%
1999
April1st to 15thNight
33%412%17%21%9%
1797
16th to endNight
25%312%26%23%7%
1800
May1st to 15thNight
30%414%21%21%7%
1800
16th to endNight
27%8%17%24%19%2
1695
June1st to 15thNight
29%8%25%23%11%1
1620
16th to endNight
33%8%22%24%10%
1620
July1st to 15thNight
28%14%32%17%6%
1609
16th to endNight
30%14%31%20%2
1772
August1st to 15thNight
28%12%33%19%5%
1788
16th to endNight
36%11%25%15%7%3
1910
September1st to 15thNight
33%10%20%18%11%5%
1836
16th to endNight
33%5%15%21%15%7%
1980
October1st to 15thNight
24%411%22%21%15%
1980
16th to endNight
25%25%15%27%23%
2276
November1st to 15thNight
28%37%19%28%12%
2435
16th to endNight
28%36%19%23%18%
2535
December1st to 15thNight
37%410%20%20%6%
2391
16th to endNight
46%47%20%15%6%
2496

Seeing (when cloud cover <= 80%)
Color Meanings:
Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
22%5%26%26%12%6%
90
16th to endDay
15%15%39%18%10%
96
February1st to 15thDay
14%12%33%22%14%3
90
16th to endDay
12%6%40%25%14%
81
March1st to 15thDay
21%7%37%27%41
90
16th to endDay
15%7%20%32%22%1
240
April1st to 15thDay
16%8%21%23%25%4
270
16th to endDay
12%318%30%28%7%
270
May1st to 15thDay
9%218%25%31%11%
288
16th to endDay
11%19%30%24%22%
331
June1st to 15thDay
13%3220%28%30%
315
16th to endDay
11%2214%29%38%
315
July1st to 15thDay
7%17%30%51%
305
16th to endDay
7%1111%35%42%
326
August1st to 15thDay
9%7%38%41%
313
16th to endDay
10%213%37%35%
332
September1st to 15thDay
8%17%17%33%32%
315
16th to endDay
10%125%36%24%
314
October1st to 15thDay
8%9%27%35%16%
315
16th to endDay
10%414%30%24%16%
168
November1st to 15thDay
15%116%33%26%6%
135
16th to endDay
6%5%28%27%21%10%
135
December1st to 15thDay
9%5%34%29%19%4
100
16th to endDay
31%6%18%23%16%3
96
January1st to 15thNight
16%7%30%33%10%
720
16th to endNight
20%9%26%34%8%
768
February1st to 15thNight
15%7%32%33%10%
704
16th to endNight
18%8%31%32%8%
631
March1st to 15thNight
16%8%27%35%10%
720
16th to endNight
11%5%23%38%20%1
608
April1st to 15thNight
13%5%23%36%19%1
539
16th to endNight
10%319%41%24%1
540
May1st to 15thNight
10%213%40%30%2
540
16th to endNight
7%7%32%44%6%
563
June1st to 15thNight
6%328%48%12%
540
16th to endNight
7%1217%51%20%
540
July1st to 15thNight
311%50%32%
510
16th to endNight
3112%49%31%
564
August1st to 15thNight
47%52%34%
539
16th to endNight
10%112%49%24%
573
September1st to 15thNight
7%15%17%45%21%
576
16th to endNight
10%1427%45%9%
717
October1st to 15thNight
9%12%35%35%7%
720
16th to endNight
9%220%32%29%4
768
November1st to 15thNight
8%317%40%25%4
760
16th to endNight
10%5%22%37%21%2
780
December1st to 15thNight
14%6%26%31%17%1
736
16th to endNight
21%5%29%30%12%
768
Page generated at 2017-12-05 09:19:03. Version ac04

Copyright 2017 A. Danko


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